1. Field of the Invention
The present invention is broadly concerned with guidance apparatus for field implements so as to quickly and precisely adjust the lateral position of the implement in the event that the implement becomes misaligned with the field rows during travel therealong. More particularly, it is concerned with such a row guidance device adapted for use with pull-behind implements coupled to swayable tractor hitch arms, wherein the guidance apparatus has row sensing means and a motive assembly for selective, lateral, momentary shifting of the hitch arms; in this fashion, the shifted hitch arms serve to lead the misaligned implement back into proper alignment with the crop rows.
2. Description of the Prior Art
It is often necessary during a growing season to cultivate the earth between row-planted crops. Many field implements have been devised for effecting such cultivation and generally include a plurality of laterally spaced apart ground-working tools designed to till or otherwise work the soil between growing rows of crop. In order to be most effective, it is of course necessary that such row implements be guided so as to insure that the ground-working tools thereof are maintained in proper position between crop rows; otherwise, the attempted cultivation may lead to unintended crop destruction. This need is particularly acute in the case of pull-behind implements which are attached to the three point hitch arms of a tractor. In such cases the tractor driver may find it extremely difficult to maintain proper implement position relative to the crop rows as the tractor and implement traverse the field. Actual field operations reveal that lateral shifting of the rear wheels of a tractor independent of front wheel steering can occur, resulting in a crabbing motion over which the tractor operator has little control. This is a particularly frustrating problem with four wheel drive tractors which are steered by means of a central pivot mechanism. Major causes of each lateral crabbing motion are ruts resulting from previous field operations such as planting, ridges resulting from ridge till farming, and slopes on hillsides or terraces.
Other types of field implements designed to operate on or around generally parallel field rows, such as planters or applicators, also benefit from row guidance and adjustment. Here again, failure to properly maintain the position of the implement relative to the crop rows can lead to crop destruction or wastage of applicator products.
A number of guidance devices have been proposed in the past effecting selective, on-the-go adjustment of pull-behind field implements. Many of these guidance devices are designed to achieve implement adjustment by pivoting of the implement about an upright axis. Experience has proved, however, that such pivot-type adjustment devices do not generally accomplish implement adjustment with sufficient rapidity, and as a consequence crop may be destroyed. It has also been known in the past to provide guidance mechanism which laterally translates the implement, as opposed to pivoting thereof. However, these prior mechanisms have proved to be extremely cumbersome and costly, owing to the need for heavy-duty cylinders and supports required for lateral translatory movement of heavy implements.